## 
## ── Column specification ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────
## cols(
##   id = col_double(),
##   age = col_double(),
##   fev = col_double(),
##   height = col_double(),
##   sex = col_character(),
##   smoke = col_character()
## )